Why is salt effective for snow removal?
In addition to the fact that a solution of a salt has a lower freezing point, the actual dissociation of the salt is exothermic. This releases some heat that will melt the ice. The the resulting liquid water will dissolve more salt, that will release more heat, etc,. etc. This is why calcium chloride is often used for ice melt. It’s dissociation is exothermic and by producing three particles in solution (1 Ca++ and 2 Cl-) it lowers the freezing point more than NaCl. ======== Follow up ========== I_space is “myth-taken”. CaCl2 is used most often by cities and departments of transportation to spread on ice and snow expressly because it DOES help melt the ice. As CaCl2 dissolves it releases heat (the dissociation is exothermic) which help melts ice.
